Machar is the leader of rebels who fought a two-year civil war against government forces under President Salva Kiir. He was rehabilitated into the government in April following a peace deal that broke down three weeks ago, leading to hundreds of deaths.

“My troops are ready to storm the capital Juba and take control,” Machar said.

Since the renewed violence between Machar’s fighters and government troops, Machar has been in hiding. “I went out of sight when I learned that the goal was to eliminate me,” he said in a telephone interview.

The deteriorating security situation in South Sudan has led to calls for a larger international force to be sent by the Intergovernmental Authority on Development (IGAD) to reinforce existing peacekeepers. Such calls have been resisted by the government.

“The implementation of the comprehensive peace agreement will not be possible without the deployment of IGAD peacekeeping forces to South Sudan,” Machar said.

He added that his soldiers were more united than ever and claimed the renewed fighting had been orchestrated by Kiir in a bid to wreck the peace agreement signed in August last year.

On Monday, Kiir replaced Machar as first vice president, a position he held in a unity government following his return to Juba, with another senior opposition figure, Taban Deng Gai, who was responsible for the peace negotiations.

Machar declared the move “illegal and a conspiracy” and renounced Gai as “not a member of the opposition group”. He said he expected the African Union and the UN to oppose Gai’s appointment.

The civil war, which began in 2013 after Kiir sacked his Cabinet and accused Machar of instigating a failed coup, was brought to an end by peace talks hosted by the IGAD trade bloc of African nations.

Machar welcomed as “significant” the bloc’s plans for a meeting in Addis Ababa, Ethiopia, next week.

The fresh fighting has seen at least 300 people killed and thousands fleeing to neighboring states.